Jaco was a student at training camp for Electric-type Pokémon, where he was trying to train an Electrike. They were the only ones that had not yet graduated because Electrike couldn't control its electricity. He met Ash and his friends when his Electrike shocked him while trying to perfect its Thunderbolt.

Truthfully, he preferred Flying-type Pokémon over Electric-types and wished that he had the chance to work with them. He also believed that his Electrike was doomed for failure. Being that Brock was a Breeder himself, Jaco was convinced that he would know that there was no hope for Electrike. But Brock didn't believe that at all and even said that Electrike was stronger than others.

Jaco proved his lack of knowledge on how to take care of Electric-type Pokémon by trying to brush Electrike with a metal brush and getting fried by the electricity in its fur. With the help of Ash, Dawn, Brock, and even James and Meowth, Jaco and Electrike gained a closer relationship and it was able to use its Thunderbolt perfectly. Later, against what James and Meowth wanted, Jessie came and attempted to steal Electrike. However, Electrike evolved into Manectric and was able to stop Jessie. Jaco's teacher, Cal, was impressed by what he and Manectric did and graduated them on the spot.

After this bond was formed, Jaco said goodbye to Manectric, for it had to live at the power plant to help generate electricity. However, he promised that he would never forget it.